The invention relates to a gas turbine engine with a geared turbofan arrangement.
Gas turbine engines with geared turbofan arrangements, in particular aircraft engines, require some means to mitigate static and dynamic loads on the gearbox (also called power gearbox) linking a turbine section of the gas turbine engine with the propulsive fan.
The gearbox with a planetary gear arrangement reduces the rotational speed from the turbine section of the gas turbine engine to the propulsive fan, so that the efficiency of the gas turbine engine is improved. With the introduction of the gearbox behind the propulsive fan, the dynamic response of the structure necessitates a bearing arrangement in which the bearings are spaced further apart. Additionally, the deflection of the structure may be a design challenge to meeting propulsive fan tip clearance requirements. During e.g. a fan blade off event, high deflections can lead to failure of the gearbox. In order to design for these deflections and loads, the gearbox size and weight needs to increase. It is known to run a thrust shaft through the center of the sun gear of the planetary gearbox to an intershaft bearing behind the sun gear. This constraints the sun gear diameter resulting from the required diameter of the thrust shaft. Furthermore, the thrust shaft design can collide with the fan blade off conditions.